1. Field of the Invention
The invention relates to shears, particularly hand-held garden or pruning shears or secateurs.
2. Description of the Prior Art
Such shears have two shear elements pivotable against one another about a pivoting axis and have engagement portions for reciprocal cutting engagement. The engagement portions form or bound in the open state of the shears a shear opening normally continuously widening from the pivoting axis and which is reduced on closing the shears, i.e. on initiating and performing the cutting process. The problem frequently arises with shears of this type that cutting material with a relatively high cutting resistance, e.g. a flower stalk or branch, tends on closing the shears to be forced out of the shear opening or mouth. In order to complete a cut it is then necessary to possibly grasp again several times or a second hand is needed for retaining the cutting material, so as to prevent a forcing of said cutting material out of the shear opening.
The object of the invention is to obviate these disadvantages of the prior art. In particular, shears are to be provided, which without any change to the otherwise familiar functions make it possible to reliably separate cutting material, such as e.g. flower stalks or branches, in a single, uninterrupted cutting process.
For solving this problem the invention proposes shears comprising two shear elements being pivotable against one another about a pivot axis, the shear elements comprising engaging portions provided for mutual cutting engagement, the shear elements, in an opened state of the shears, forming a shear opening widening from the pivot axis, the shear opening becoming smaller upon closing the shears, the shears further comprising holding means separate from the shear elements, the holding means being adapted such that the holding means apply a holding force for retaining cutting material introduced into the shear opening essentially only until the cutting process is completed. Preferred further developments are given in the dependent claims. By reference, the wording of all the claims is hereby made into part of the content of the description.
Consequently shears according to the invention are characterized in that there are separate holding means essentially only active up to the completion of a cutting process for holding cutting material introduced into the shear opening during the closing of the shears. As a result the cutting material is reliably held in the shear opening during the closing process of the shears, so that the described sliding or forcing out from the shear mouth is avoided or at least largely prevented. Consequently a cut can be completed in a single shear closing process and the cutting material can be completely cut through. However, as soon as the cutting material is cut through, the holding or retaining action of the holding means automatically decreases to such an extent that the cut parts of the cutting material, precisely as in conventional shears, automatically drop or the shears can be moved away from the cutting material without it being necessary to open the shears again beforehand.
Whereas in the case of shears with toothed or serrated cutting edges such a holding action can at least partly be obtained through the teeth of the engagement portions, through the inventive provision of separate holding means, i.e. holding means provided additionally to the shear elements, the action of the invention can be attained with any shear type, particularly also shears with smooth cutting edges, which are preferred for many cutting operations, particularly in the garden sector, as a result of the smooth, unfrayed cut which can be produced.
Due to the fact that the cutting material is released from the shears automatically on completing a cut without having to reopen the shears again, the shears according to the invention differ clearly from other known shears, where separate holding means are provided in order to retain on the shears the cut material after completing the cut for as long as said shears remain closed. An example for such garden shears or secateurs, particularly constructed as rose shears, is disclosed by DE 81 11 164. The crop shears according to DE 43 02 136 is so constructed through holding elements running parallel to the cutting edges that a clamping action is exerted on the separated portions of cutting material after completing the cut and with the shears closed, so that it is possible to prevent the dropping of the cut portion, e.g. when harvesting tree fruit. U.S. Pat. Nos. 1,458,878 and 1,151,874 disclose such shears with holding means making it possible to retain cut through cutting material with the shears closed and to transport same away with the aid of the closed shears. Such shears are essentially based on the holding or retaining function of the shears after the completion of the cut and require a rethink on the part of the user with respect to the handling compared with conventional shears without holding means. However, in the case of the shears according to the invention the holding means are only active essentially during the cutting process, i.e. up to the complete cutting through of the cutting material and then the shears behave in much the same way as shears without holding means, so that a user accustomed to conventional holding means-free shears when using the shears according to the invention does not have to rethink his procedure. However, when using shears according to the invention cutting work can be reliably and rapidly performed, because in each case it is merely necessary to apply the shears in order to initiate and complete the cutting process. A user also regularly has the other hand free, so that he can hold on when working in the crowns of trees, so that as a result of the shears according to the invention working safety is improved.
According to a preferred development the holding means form at least one elastically flexible holding surface and are so constructed and positioned that the not or not completely cut cutting material are surface-pressed onto the holding surface through the closing of the shears or the reduction of the shear opening by means of the shear elements whilst building up friction and after completing the cut and whilst decreasing the contact pressure there can be a release from the holding surface. The elastically flexible holding surface makes it possible to produce a holding force, which increases as the cutting pressure rises and with a corresponding rising tendency to press the cutting material out of the shear opening and correspondingly decreases on reducing the cutting pressure, i.e. after cutting through the cutting material to such an extent that the holding function is eliminated and the cutting material is released. Thus, a slip inhibition at least partly dependent on the cutting pressure is created.
The holding means are preferably formed in that at least one separate, rubber-like holding element is provided, which is fitted in preferably detachable or replaceable manner to one of the shear elements. The holding element can be made essentially of rubber or a rubber-like plastic and/or is constructed in one piece. Such rubber-like fabricated parts are inexpensively manufacturable in any appropriate shape and can form with their outer faces the elastically flexible holding surface.
There are numerous possibilities for fitting such rubber-like holding elements to the shears or a shear element. According to a further development on at least one of the shear elements is formed at least one reception opening for the preferably captive reception of at least one rubber-like holding element. The receptacle can be constructed in integral manner with the body of the shear element, e.g. as a bore or a bore-like opening, in which can be inserted in slightly compressed and consequently largely self-holding manner a rubber-like element. Thus, a holding element can be so spatially integrated into a shear element that it is substantially surrounded by the shear element material and essentially only exposes a portion with the holding surface at an appropriate location. Appropriately the reception opening is oriented in such a way that the holding element can be more firmly pressed into the reception opening by the cutting pressure on cutting and is consequently held in captive manner.
It is also possible to provide at least one fastening device for fastening at least one rubber-like holding element to the shear element, which is separate from the latter and is preferably detachably fastenable thereto. In this case it is merely necessary to provide on the shear element devices, e.g. in the form of tapped holes, which permit a fastening of the fastening device. Together with the shear element, the latter can form a reception opening for the holding element and act in the manner of a clamping device, so as to secure the holding element in captive manner on the shear element.
It is also possible for the holding means to have at least one rubber-like holding element, which can be fitted in self-retaining manner on a shear element, it being in particular attachable or mountable and/or clampable on the shear element. In this case there is no need for separate reception openings and/or separate fastening devices-on the shear element, because the holding element itself acts in the manner of a fastening device.
For protecting the holding elements against overloading during cutting, according to a further development it is possible to place a holding element in an associated reception opening in such a way that a projecting portion of the holding element forming the holding surface projects slightly in the vicinity of a mouth of the reception opening located on the engagement surface of the shear element over said shear element surface. The height of the projecting portion is preferably dimensioned in such a way that, as a result of the cutting pressure, the holding element can be compressed to such an extent that it is surface-flush in the reception opening. This creates a path limitation for compression and therefore protects the holding element against overloading. The holding function of the holding element is retained, because the compressed holding element still presses in the vicinity of the mouth or opening on the cutting material resting on the engagement surface and secures the same.
It also contributes to protecting holding means against damage when, according to a further development, holding means are positioned outside or alongside a preferably elongated cutting area, where a cutting engagement takes place between the shear elements. Thus, no cutting edge of a shear element acts directly on the holding means, so that damage is avoided. However, preferably the holding means are so close, e.g. with a small lateral spacing with respect to the cutting area, that the cutting pressure produced by a cutting edge on the cutting material in the case of a suitable flexural rigidity of the cutting material can be transferred to the area of the holding surface on the holding means.
It may be sufficient to only provide holding means on one side of the cutting area, so that on the opposite side the cutting material is directly supported on a shear element. Such constructions are particularly cost-effective. However, it is also possible to provide holding means on both sides of the cutting area. As an alternative and optionally also additionally to laterally positioned holding means, holding means can also be provided in the cutting area and then with the holding surface simultaneously form a mating surface for a cutting edge of the other shear element. As a function of the shear construction and the desired use, a choice can be made between these possibilities.
In the case of a further development explained in conjunction with the embodiments, the shears are constructed as anvil shears, in that only one shear element as an engaging portion has a preferably smooth cutting edge and on the other shear element, the anvil, is formed a mating surface for the cutting edge which does not itself cut and on which the cutting edge can be pressed for producing a one-sided cutting engagement in the manner of a knife. The normally solid anvil, which is wide compared with normal cutting edges, forms a wide cutting support on which the cutting material is supported during cutting over a certain length at right angles to the cutting area. Preferably the holding means are exclusively located on the shear element constructed as an anvil and which as a result of its width and solid construction offers adequate space for the provision of reception openings for holding elements. The shear element provided with a cutting edge can remain unchanged compared with conventional shears of similar design and construction. With such embodiments the holding means are consequently fitted to only one of the shear elements. However, it is also possible to provide identical or different holding means, which can appropriately cooperate, on both shear elements.
It is also possible to construct the shears as doubled edged shears, in which each shear element as an engaging portion has a cutting edge or blade, the engaging portions sliding past one another in scissor-like manner during cutting. In particular, double edged shears can be constructed with a narrow upper blade and a lower blade with a wide, only slightly bevelled blade edge, which is generally constructed in a more solid manner than the upper blade in the cutting edge area. It is here once again possible to use the more solid shear element, namely the lower blade, for fitting holding means.
These and further features can be gathered from the claims, description and drawings and the individual features, both singly and in the form of subcombinations, can be implemented in an embodiment of the invention and in other fields and can represent advantageous constructions.